BHF poll ...... the fin debate .

[miatanut]

Originally Posted by Maelochs

So ... they were willing to examine their own results in the face of real-world evidence .. but if I or another poster does the same, we are automatically wrong? Yeah, #forumlogic.

I might not have a supercomputer or flow-modelling software, but I can tell the difference between a car on the road and a car doing flips 20 feet in the air.

I would say your post is Exhibit A for forumlogic. 'I don't care how much CFD and wind tunnel testing went into this, based on what I see on a video clip of one accident, the BHF is a bad idea.'

How about we let the aerodynamicists analyze this incident in the coming weeks, including precise recreation of it to determine how all the various factors interacted, and then learn from it and determine how to proceed? Maybe this was the crash where the safety belts killed somebody by trapping them in the car, but in the vast majority of incidents they wouldn't. Maybe they will determine this is a more likely incident then they thought and there is a problem.

You know the team aerodynamicists are up to their eyeballs in this. If they thought the BHF was a bad idea, they would have communicated it to ACO. Maybe they did through some back channel and ACO didn't listen to them. It wouldn't be the first time. In that case, they will go public with this in the next couple days and we will all know. If we don't hear anything, likely it means the team aerodynamicists are on board with this concept and everybody needs to figure out how to reduce the chances of this sort of incident.

To say the NASCAR aerodynamicists didn't happen on their current solution on the first try doesn't mean they made any sort of mistake. They made a mistake if they made the situation worse. If they were evolving the design over a series of generations to make it work better, that's simply the design process.

The only people I would call "wrong" are the people who hold up this incident as proof the BHF is a bad idea without first studying it in CFD and the wind tunnel, to determine if the BHF helped or made things worse, and if it made things worse, then evaluating if this is an unusual incident or a very common one where a solution that makes things worse is unacceptable.

[prototype]

My understanding of the fins are that when a car begins to rotate or spin, the pressure on the side of the fin will encourage the car to straighten and avoid these yaw to airborne incidents.

However, when an accident like the Ferarri and Toyota at Mulsanne spins the car 90 degrees it looks like the fin did more harm than good. I thought the fin slowed the top of the Toyota down while the bottom of the car began to lift as it was moving faster than the top. Shortly there after, enough air hits the underside of the car to quickly make the car airborne. It would be really interesting to see this same incident with no BHF on the Toyota.

The good news is the ACO will have access to even more data to implement with a new set of rues in 2014.

Full disclosure: I have nothing against the aesthetics of the BHF.

[RacingSportsCars]

Originally Posted by cdsvg

I really dont understand how the armchair fan can possibly say things like this without seeing CFD/wind tunnel figures. The fins weren't implemented based on intuition, these things are tested.

Well, thanks for sharing with us various things that you do not understand. I am just not sure everybody is interested in your weaknesses, so I recommend to stay away with such statements next time. I feel there is not much to discuss or answer to this, which was apparently supposed to be a reaction to my earlier comment. Sorry, I am not able to discuss with people, who take something as "dogma" because "somebody" told them and anybody trying to put something new into this is just purely satirised.

I like most other comments of positive and creative people that are evaluating reasons why fins might not work. It was impossible not to notice that both Toyota and Ferrari had similar accident at similar speed and the Ferrari behaved much better. Well, it is a bit heavier but can you remember prototypes of the past (late 1960s until 2004) flying so easily when going sideways? I cannot (yes, there were some flips, Morton in Nissan GTP for example, but I do not think those were flips of the same kind as recently seen among the modern LMPs). Not sure if Bellof's fatal accident was of the similar type as this one in Le Mans 2012. Current cars are surely much safer (better & stronger construction, circuits are also much more suitable to minimise accident consequences) to avoid fatalities of the past but I cannot imagine any Group C or former Group 6 car would fly so easily. Having Bellof collidied Ickx these days, most likely they would fly into the trees outside Eau Rouge... :-(

Formula 1 had also implemented fins and after two years they came to a conclusion it does help nothing (statement I have read, not studied deeply) - so what people believing in dogmas would say here?

I hope new studies will be performed by competent people and they will come with better solutions before 2014.

By the way, does anybody know why in 2004 the ride height (ground clearance) between the front and rear wheels was made mandatory bigger than it used to have been before in the past and still is applied among GT cars? I am not sure about this but I feel it does not help side stability as well. GT's at similar speeds are surely much stable in high speed spins.

[Dead-Eye]

Originally Posted by RacingSportsCars

Formula 1 had also implemented fins and after two years they came to a conclusion it does help nothing (statement I have read, not studied deeply) - so what people believing in dogmas would say here?

The F1 fins were there purely for performance reasons, not for safety. You're not helping your argument by muddying the water that way.

[RacingSportsCars]

Originally Posted by Dead-Eye

The F1 fins were there purely for performance reasons, not for safety. You're not helping your argument by muddying the water that way.

Which is why, I said I have not studied it. But I have read it this way - I was not sure what they were supposed to help or not. F1 have no flipping problems I think.

[RacingSportsCars]

Originally Posted by Dead-Eye

The F1 fins were there purely for performance reasons, not for safety. You're not helping your argument by muddying the water that way.

In fact I found your comment also of no help (if I did not want to mention it, I would not do, it is my thing, not yours), so I tried to search a bit. I remember the F1 fins were originally implemented by some teams only finding in it some advantage, then it was made mandatory and then they disappeared. But what I found here (http://answers.yahoo.com/question/in...8153803AA8cxDb) suggest that those fins made the car even unstable at some parts of the tracks. citation: "Another con of the shark fin is that it is heavily effected by crosswinds. Making the car heavily unstable in certain areas of the track."

I would appreciate more comments about this by those who are more into F1. Just avoid personal attacks like those that really add nothing new to the topic.

EDIT: Having read that discussion about F1 fins deeper, it appears that there was a large variety of opinions about how they actually work - but they are all 2 years old. What was the final conclusion when they abandoned them? I can's see it to be only performance reasons - it helped some cars but did not to some others.... (based on those comments - I really did not care much when F1 ran them).

[cdsvg]

Originally Posted by Maelochs

Evidence is a useful tool for evaluating claims. if some folks claim certain changes will prevent a certain reaction in a certain situation, and that exact thing then happens, only a fool wouldn't look into it.

So ... they were willing to examine their own results in the face of real-world evidence .. but if I or another poster does the same, we are automatically wrong? Yeah, #forumlogic.

I might not have a supercomputer or flow-modelling software, but I can tell the difference between a car on the road and a car doing flips 20 feet in the air.

The fins increase the speed required for the car to take flight when in yaw. They dont eliminate it. I would say its thoroughly unscientific to take one example of takeoff at very high speed, and assume that the fin *failed* to work. Do you not consider the possibility that the incident was less severe with the fin? Or does this one example prove to you that they got it all wrong and the armchair analysts were right?

Originally Posted by prototype

My understanding of the fins are that when a car begins to rotate or spin, the pressure on the side of the fin will encourage the car to straighten and avoid these yaw to airborne incidents.

However, when an accident like the Ferarri and Toyota at Mulsanne spins the car 90 degrees it looks like the fin did more harm than good. I thought the fin slowed the top of the Toyota down while the bottom of the car began to lift as it was moving faster than the top. Shortly there after, enough air hits the underside of the car to quickly make the car airborne. It would be really interesting to see this same incident with no BHF on the Toyota.

The good news is the ACO will have access to even more data to implement with a new set of rues in 2014.

Full disclosure: I have nothing against the aesthetics of the BHF.

The fins are designed to work in yaw by creating a high pressure area on top of the leading sidepod, combined with the curved underside of the floor in side profile creating a low pressure area under the car.

Originally Posted by RacingSportsCars

Well, thanks for sharing with us various things that you do not understand. I am just not sure everybody is interested in your weaknesses, so I recommend to stay away with such statements next time. I feel there is not much to discuss or answer to this, which was apparently supposed to be a reaction to my earlier comment. Sorry, I am not able to discuss with people, who take something as "dogma" because "somebody" told them and anybody trying to put something new into this is just purely satirised.

Please stay away from the personal attacks. This is nothing to do with 'dogma', this is about not making kneejerk emotional reactions to such incidents, and considering all the evidence for what is an issue of aerodynamics.

Originally Posted by miatanut

I would say your post is Exhibit A for forumlogic. 'I don't care how much CFD and wind tunnel testing went into this, based on what I see on a video clip of one accident, the BHF is a bad idea.'

The only people I would call "wrong" are the people who hold up this incident as proof the BHF is a bad idea without first studying it in CFD and the wind tunnel, to determine if the BHF helped or made things worse, and if it made things worse, then evaluating if this is an unusual incident or a very common one where a solution that makes things worse is unacceptable.

Exactly.

For the record I think the fins are a band-aid fix and I would like to see a more elegant solution, but lets not forget this is a very complex scientific problem.

[RacingSportsCars]

Originally Posted by cdsvg

For the record I think the fins are a band-aid fix and I would like to see a more elegant solution, but lets not forget this is a very complex scientific problem.

Could you link to some proof that those fins really no doubt do what you are trying to claim?

I consider current prototype aero rules generally wrong but maybe I am missing something. I do not mean only fins but general aerodynamic restrictions. And I do not base it on one accident but on general behaviour of the modern cars and those for example from the Group C days, especially when the driver lose control. Maybe current aero designs are too advanced and it is impossible to get the Group C days back. (btw., have you seen the Legend Race accident? Would that Spice been made to the current rules, I would not be surprised it 'airborned' as well).

Today's Grand-Am are closer to the old prototypes and while I admit I do not follow them much, I cannot recall seeing any accidents with a huge flip circulating around.

Personally, I believe that the fins will be abandoned sooner or later. Regardless what we are discussing here.

[GTfour]

I think it's very clear, after the Toyota/Ferrari incident of last Saturday, that them b#**ugly fins have next to no effect on the cars aerodynamic behaviour during highspeed crash situations. I therefore believe them to be totally useless and they should be banned immediatly.

[The Badger]

They may work in some situations , obviously not in the situation we had last Saturday ..... there are some who say they work , so what was that blue thing flying through the air ..... Santa Claus !!!

[cdsvg]

Originally Posted by RacingSportsCars

Could you link to some proof that those fins really no doubt do what you are trying to claim?

I consider current prototype aero rules generally wrong but maybe I am missing something. I do not mean only fins but general aerodynamic restrictions. And I do not base it on one accident but on general behaviour of the modern cars and those for example from the Group C days, especially when the driver lose control. Maybe current aero designs are too advanced and it is impossible to get the Group C days back. (btw., have you seen the Legend Race accident? Would that Spice been made to the current rules, I would not be surprised it 'airborned' as well).

Today's Grand-Am are closer to the old prototypes and while I admit I do not follow them much, I cannot recall seeing any accidents with a huge flip circulating around.

Personally, I believe that the fins will be abandoned sooner or later. Regardless what we are discussing here.

All I am 'claiming' is that this incident in isolation doesnt indicate that the fins are useless. The judgement on their effectiveness takes more than anecdotal evidence.

This: http://issuu.com/racecargraphic/docs...ro_study.final might be a place to start if you want to know more.

[The Badger]

Originally Posted by RacingSportsCars

Personally, I believe that the fins will be abandoned sooner or later. Regardless what we are discussing here.

So do I ..... when a proper thorough study is done , and not a half assed temp fix that they are .

48 to 16 against the fins in the poll so far . I know that has no bearing on the safety , but the poll was about like or dont like after all .

So far , my point is being proven , the vast majority dont like them .

[RacingSportsCars]

Originally Posted by cdsvg

All I am 'claiming' is that this incident in isolation doesnt indicate that the fins are useless. The judgement on their effectiveness takes more than anecdotal evidence.

This: http://issuu.com/racecargraphic/docs...ro_study.final might be a place to start if you want to know more.

Thanks, I will study this.

[RacingSportsCars]

Originally Posted by The Badger

So do I ..... when a proper thorough study is done , and not a half assed temp fix that they are .

48 to 16 against the fins in the poll so far . I know that has no bearing on the safety , but the poll was about like or dont like after all .

So far , my point is being proven , the vast majority dont like them .

Unfortunately, many people think the fins make cars ugly. I had a friend who is mainly into touring cars, and partly GTs, watching with me this year's Le Mans and he repeatedly claimed that the cars with the fins are really ugly. His negative emotion was so strong that he apparently could not resists saying that repeatedly. Nothing pleasant for me, a sports car guy who was used to hear only positive comments on my favourite prototype cars appearance.

[cdsvg]

Originally Posted by RacingSportsCars

Unfortunately, many people think the fins make cars ugly. I had a friend who is mainly into touring cars, and partly GTs, watching with me this year's Le Mans and he repeatedly claimed that the cars with the fins are really ugly. His negative emotion was so strong that he apparently could not resists saying that repeatedly. Nothing pleasant for me, a sports car guy who was used to hear only positive comments on my favourite prototype cars appearance.

You wont hear me disagreeing with you about the aesthetics!